基于流化床热解的中药渣两段气化基础研究

以中药渣为原料,研究了流化床热解和固定床半焦催化/重整焦油及半焦气化的特性,特别是对固定床重整前后焦油中组分的变化进行了分析。结果表明,随着热解气体在固定床半焦中停留时间从0 s延长到0.95 s,焦油中-OH、C-H、C-O、C=O和C=C官能团的含量显著减少,芳香类物质含量明显增加;向固定床中加入水蒸气后,焦油中芳香类、C-O和羟基-OH官能团的含量增加;而加入氧气后,焦油中羟基-OH、C-H、羰基C=O、C=C和C-O官能团物质含量变化不大,但芳烃类物质明显增多。虽然向固定床中加入水蒸气或氧气均能降低焦油含量,但水蒸气的作用稍弱,两者联合对焦油脱除和半焦气化效果更好,生成的燃气中基本不含焦油。

Fundamental study on Chinese herb residue pyrolysis and gasification by combining fluidized bed and fixed bed

The tar and char from a fluidized bed Chinese herb residue (CHR) pyrolysis were cracked and gasified in a fixed char bed. The change in chemical species of tar before and after passing through a fixed char bed was analyzed. The results show that increasing the residence time of tar and pyrolysis gas in the char bed from 0 s to 0.95 s causes a significant decrease in the chemical species containing -OH, C-H, C-O, C=O and C=C groups, but leads to an obvious increase in the aromatic species. Introducing steam into the char bed results in the formation of more species containing aromatic rings, C-O and -OH groups, while adding the oxygen to the atmosphere increases the amount of aromatic components but has little effect on the amount of species containing -OH, C-H, C=O, C=C and C-O. Both steam and oxygen are effective to remove tar from the gasification gas, but the effect of steam is relatively weaker. Introducing steam together with oxygen will have a rather higher tar removal efficiency, and the tar in the producer gas can be ignored.